In our earlier UK Patent No 2 259 064, we disclosed and claimed apparatus in which the position of a rear-view mirror was controlled according to the angle between the tractor and the trailer so that the driver can always see, using the mirror, along the side of the trailer on the inside of the turn. This was done by sensing the rotation of the trailer relative to the tractor in an articulated road vehicle. Each mirror was provided with a drive means comprising an arcuate gear member driven by a worm gear rotated by an electric motor, a potentiometer serving to provide an electrical signal indicative of the angular position of the mirror.
A problem with constructing such an arrangement is that of eliminating backlash in the gears without making the cost excessive. It is also desirable to be able to allow for impact to deflect the mirror without damaging it, and to permit rapid restoration of the desired alignment of the deflected mirror.
The present invention seeks to overcome these problems.